1. Field of the Invention
The invention relates generally to an integrated lead suspension (ILS) for connection of read/write circuitry to the read/write head in a magnetic recording disk drive, and more particularly to an ILS with interleaved coplanar electrically conductive lines or traces.
2. Description of the Related Art
In magnetic recording disk drives the read/write head is formed on an air-bearing slider that rides on a thin film of air above the rotating disk. A mechanical suspension comprised of a flexure with a gimbal at its end connects the slider to the disk drive's actuator arm. The slider is attached to the gimbal which allows for slight movement on the air bearing as the disk rotates.
Electrical connection is required between the read/write circuitry, typically a read pre-amplifier/write driver module or chip, and the read and write elements on the slider. A suspension that integrates the mechanical connection with the electrical connection is called an integrated lead suspension (ILS). A typical ILS is a generally flexible laminate of a conductive metal substrate like stainless steel, an insulating dielectric layer like polyimide, and electrically conductive copper lines or traces patterned on the dielectric layer.
The write driver circuitry typically provides a single-point input to the ILS for each of the positive and negative write signals (+W and −W). The write driver circuitry provides current through the ILS and then to the write element or head. The write driver circuitry power supply voltage and performance of the current through the write head depends on the characteristic impedance of the ILS traces. Therefore, it is desirable to have an ILS that has a wider characteristic impedance range with low signal losses for the traces carrying the current signal to the write head.